Catalytic composition based on chromium and a ligand based on phosphine and its use in a method for producing octenes

Abstract

The invention pertains to a composition that comprises at least one chromium precursor, at least one heteroatomic ligand, and, optionally, at least one activator. The invention also pertains to the method for preparation of the composition in accordance with the invention and the use of said composition in a method for oligomerization of olefins.

The invention claimed is: 
     
       1. Composition comprising:
 at least one chromium precursor, 
 at least one heteroatomicligand described by the general formula (I)
   (R 1 ) 2 P—O—(CH 2 ) n —N[P(R 2 ) 2 ] 2  
 
 
 
       in which the groups R 1  and R 2 , identical or not, bonded together or not, are selected from among cyclic, linear, or branched alkyl groups or aromatic groups, and n is an integer greater than or equal to 1 and less than or equal to 15;
 and, optionally, at least one activator. 
 
     
     
       2. Composition in accordance with  claim 1 , in which the molar ratio between the ligand and the chromium precursor is between 0.01 and 100. 
     
     
       3. Composition in accordance with  claim 1 , in which the molar ratio between the activator and the chromium precursor is between 1 and 10,000. 
     
     
       4. Composition in accordance with  claim 1 , in which the chromium precursor is selected from among CrCl 3 , CrCl 3 (tetrahydrofuran) 3 , Cr(acetylacetonate) 3 , Cr(naphthenate) 3 , Cr(2-ethylhexanoate) 3 , and Cr(acetate) 3 . 
     
     
       5. Composition in accordance with  claim 1 , in which the activator agent is selected from among the tris(hydrocarbyl)aluminum compounds, the chlorinated or brominated compounds of hydrocarbylaluminum, aluminum halides, aluminoxanes, the organoboronated compounds, and the organic compounds that are capable of providing a proton, taken individually or in a mixture. 
     
     
       6. Method for preparing the composition according to  claim 1 , comprising bringing the following into contact:
 the at least one chromium precursor; 
 with the at least one heteroatomic ligand that is described by the general formula (I) 
 and, optionally, with the at least one activator. 
 
     
     
       7. Method in accordance with  claim 6 , in which the brining into contact is carried out at a temperature of between −40° C. and +150° C. 
     
     
       8. Method for oligomerization of an olefinic feedstock that comprises olefins having between 2 and 10 carbon atoms comprising:
 oligomerizing the olefinic feedstock with the composition in accordance with  claim 1 , wherein the oligomerizing is run at a total pressure of between atmospheric pressure and 20 MPa and at a temperature of between −40° C. and +250° C. 
 
     
     
       9. Method in accordance with  claim 8 , in which the method is a method for tetramerization of ethylene into octene-1.